package com.yaofeng.mybatis.filter;

import com.alibaba.fastjson.JSONObject;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.yaofeng.mybatis.common.ErrorCodeEnum;
import com.yaofeng.mybatis.common.ResponseInfo;
import com.yaofeng.mybatis.jwt.JWTToken;
import com.yaofeng.mybatis.modules.sys.entity.User;
import com.yaofeng.mybatis.modules.sys.service.IUserService;
import com.yaofeng.mybatis.util.*;
import lombok.extern.slf4j.Slf4j;
import org.apache.shiro.authc.AuthenticationException;
import org.apache.shiro.web.filter.authc.BasicHttpAuthenticationFilter;
import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.RequestMethod;
import javax.servlet.ServletOutputStream;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.Date;

/**
 * Created by yaofeng on 2019/8/15.
 * 代码的执行流程preHandle->isAccessAllowed->isLoginAttempt->executeLogin
 */
@Slf4j
public class JWTFilter extends BasicHttpAuthenticationFilter {

    /**
     *
     */
    @Override
    protected boolean executeLogin(ServletRequest request, ServletResponse response) throws AuthenticationException {
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        String authorization = httpServletRequest.getHeader("Authorization");
        JWTToken token = new JWTToken(authorization);
        /**
         * 在规定token有效时间内,前2分钟刷新token
         */
        // 获取token过期时间
        Date expiresDate  =  JWTUtil.getExpiresDate(authorization);
        if(expiresDate==null){
            // 提交给realm进行登入，如果错误他会抛出异常并被捕获
            getSubject(request, response).login(token);
        }
        Date  currentDateBefore2Minute = DateUtils.addDateMinutes(new Date(),Constants.REFRESH_VALID_TOKEN_TIME_TWO_MINUTES_EARLIER);
        // 如果间隔时间在过期时间内
        if(System.currentTimeMillis()-expiresDate.getTime()<JWTUtil.EXPIRE_TIME){
            if(currentDateBefore2Minute.after(expiresDate)){
                // 获取loginName
                String loginName = JWTUtil.getLoginName(authorization);
                IUserService  iUserService  =  ApplicationContextUtil.getBean(IUserService.class);
                User user = iUserService.getOne(new QueryWrapper<User>().lambda().eq(User::getLoginName,loginName));
                // 刷新token
                token = new JWTToken(JWTUtil.sign(user.getLoginName(),user.getUserPassword()));
                // 记录新token
                HttpContextUtils.getHttpServletRequest().setAttribute(Constants.REFRESH_TOKEN,token.getPrincipal());
            }
        }

        // 提交给realm进行登入，如果错误他会抛出异常并被捕获
        getSubject(request, response).login(token);
        // 如果没有抛出异常则代表登入成功，返回true
        return true;
    }

    /**
     * 判断用户是否想要登入。
     * 检测header里面是否包含Authorization字段即可
     */
    @Override
    protected boolean isLoginAttempt(ServletRequest request, ServletResponse response) {
        HttpServletRequest req = (HttpServletRequest) request;
        String authorization = req.getHeader("Authorization");
        return authorization != null;
    }

    /**
     * 方案一
     * 这里我们详细说明下为什么最终返回的都是true，即允许访问
     * 例如我们提供一个地址 GET /article
     * 登入用户和游客看到的内容是不同的
     * 如果在这里返回了false，请求会被直接拦截，用户看不到任何东西
     * 所以我们在这里返回true，Controller中可以通过 subject.isAuthenticated() 来判断用户是否登入
     * 如果有些资源只有登入用户才能访问，我们只需要在方法上面加上 @RequiresAuthentication 注解即可
     * 但是这样做有一个缺点，就是不能够对GET,POST等请求进行分别过滤鉴权(因为我们重写了官方的方法)，但实际上对应用影响不大
     * <p>
     * <p>
     * 方案 二 通过注解方式不要登录验证的匿名登录
     * 通过requestMappingHandlerMapping映射关系去处理 请求  要通过判断返回是true还是false
     */
    @Override
    protected boolean isAccessAllowed(ServletRequest request, ServletResponse response, Object mappedValue) {
        /*// 是否匿名访问  方案二
        AtomicReference<Boolean> anon = new AtomicReference<>(false);
        // 获取系统中所有 requestMappingHandlerMapping 映射关系
        AbstractHandlerMethodMapping<RequestMappingInfo> objHandlerMethodMapping = (AbstractHandlerMethodMapping<RequestMappingInfo>)ApplicationContextUtil.getBean("requestMappingHandlerMapping");
        Map<RequestMappingInfo, HandlerMethod> mapRet = objHandlerMethodMapping.getHandlerMethods();
         // 遍历map
         mapRet.forEach((k,v)->{
             String uri   =  k.getPatternsCondition().getPatterns().iterator().next();
             log.info("uri:{}",uri);
             log.info("requesturi:{}",((HttpServletRequest)request).getRequestURI());
             if(uri.equals(((HttpServletRequest)request).getRequestURI())){
                 log.info("method:{}",v.getMethod());
                 Log logAnno = v.getMethodAnnotation(Log.class);
                 if(logAnno != null && logAnno.ignore()){
                     log.info("isAccessAllowed->:{}",v.getMethod());
                 }
                 anon.set(true);
             }

         });
        if(anon.get()){
            log.info("anon:{}",anon.get());
            return  true;
        }

        if (isLoginAttempt(request, response)) {
            try {
                executeLogin(request, response);
            } catch (AuthenticationException e) {
                response401(request, response,e);
            }
            return true;
        }else{
            return false;
        }*/
        if (isLoginAttempt(request, response)) {
            try {
                executeLogin(request, response);
            } catch (AuthenticationException e) {
                response401(request, response, e);
            }

        }
        return true;
    }

    /**
     * 方案 二
     * 当isAccessAllowed 返回false时调用此方法(用户未登录，需要先登录)
     *
     * @param request
     * @param response
     * @return
     * @throws Exception
     */
    @Override
    protected boolean onAccessDenied(ServletRequest request, ServletResponse response) throws Exception {
        HttpServletResponse httpServletResponse = (HttpServletResponse) response;
        httpServletResponse.setCharacterEncoding("UTF-8");
        httpServletResponse.setContentType("application/json");
        httpServletResponse.getWriter().write(JSONObject.toJSONString(ResponseInfo.fail(ErrorCodeEnum.NOT_LOG.getErrMsg())));
        return false;

    }

    /**
     * 对跨域提供支持
     */
    @Override
    protected boolean preHandle(ServletRequest request, ServletResponse response) throws Exception {
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        HttpServletResponse httpServletResponse = (HttpServletResponse) response;
        httpServletResponse.setHeader("Access-control-Allow-Origin", httpServletRequest.getHeader("Origin"));
        httpServletResponse.setHeader("Access-Control-Allow-Methods", "GET,POST,OPTIONS,PUT,DELETE");
        httpServletResponse.setHeader("Access-Control-Allow-Headers", httpServletRequest.getHeader("Access-Control-Request-Headers"));
        // 跨域时会首先发送一个option请求，这里我们给option请求直接返回正常状态
        if (httpServletRequest.getMethod().equals(RequestMethod.OPTIONS.name())) {
            httpServletResponse.setStatus(HttpStatus.OK.value());
            return false;
        }
        return super.preHandle(request, response);
    }

    /**
     * 将非法请求跳转到 /401
     */
    private void response401(ServletRequest req, ServletResponse resp, Exception ex) {
        ServletOutputStream out = null;
        try {
            resp.setCharacterEncoding("utf-8");
            out = resp.getOutputStream();
            resp.setContentType("application/json; charset=utf-8");
            out.print(JSONObject.toJSONString(ResponseInfo.fail(ex.getMessage())));
            out.flush();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (out != null) {
                try {
                    out.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }


    }


}
